When an undergrad student, I was shooting a recital being held in the chapel, as an employee of the school's PR department, with the writer in tow. We sat in the front row, off to one side, and I shot with the quietest body I owned, no drive, flash or tripod. I couldn't have been less intrusive or conspicuous while getting the shots requested. Afterward I was dressed down loudly and publically by a student for "upsetting" a flutist during her performance.
While on a multi-day shoot for a bank's annual report, I was taken to many sites where the employee from the marketing department and I would enter the branch or office where we would meet the manager and explain our purpose and legitimacy in photographing the building, before we set up any gear. While I don't think it is illegal to photograph a bank building, it does cause stress among the employees (my wife is a bank manager now so I well understand this), and can result in being queried by the local LEOs about one's intent and purpose (everyone has a job to do, right?). The only exception to this meet and greet routine was in the case of a small community bank that was in negotiations with the larger bank for a merger/acquisition that the employees were not yet aware of, but the larger bank needed a shot of before the report went to print. In this case, we literally conducted a drive-by shooting so we wouldn't have to explain ourselves. That shot was as good as one would expect through the glass of a moving vehicle.